Adaptive Security for Wireless Sensor Networks

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Adaptive Security for Wireless Sensor Networks

• Master Thesis June 2006

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Table of contents

• I Introduction
• II Security Aspects in WSN
• III The Proposal
• - Security Manager
• - Context Monitoring Algorithm
• - Adaptive Security System Building Blocks
• - Building Blocks Information procedure
  diagram
• IV Results
• V Conclusions

2/19
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Introduction
Introduction

• Sensor nodes are able to improve lots of
  applications (medical, industrial, intelligent
  environments)
• Work is focused on the adaptive security of a
  wireless sensor networks
• A new feature is introduced the Security Manager
• One specific scenarios has been studied
  healthcare monitoring

Security in WSN
Our Proposal
Results
Conclusions
3/19
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Security aspects
Introduction

• Weak points of Security in WSN
• Communication between sensor nodes and the
  aggregator.
• The aptitude of a network to counterattack.
• The ability to protect privacy
• Real need for a secure and an easy-to-use network
  
• We assume that the base station is a
  point-of-trust
• The nodes must have robust solution against
  attacks
• Use of authentication protocols and cryptography
  techniques

Security in WSN
Our Proposal
Results
Conclusions
4/19
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Our Proposal
Introduction

• Security Manager
• Context Monitoring Algorithm
• Adaptive Security System building blocks
• Building blocks and information procedure
  diagram

Security in WSN
Our Proposal
Results
Conclusions
5/19
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Authentication and Encryption Processes
Introduction
Security in WSN
Our Proposal
Results
Conclusions
6/19
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Security Levels

• Three Levels of Security
• Low Level
• RC5 - 32/6/3
• Medium Level
• RC5 - 32/6/5
• High Level
• RC5 - 32/12/5

Introduction
Security in WSN
Our Proposal
Results
Conclusions
7/19
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The Context Monitoring Algorithm
Introduction

• Determine an adaptive reaction to maintain the
  networks integrity and functionalities.
• Responsible for
• Tracking and Reporting the networks status
• Checking the anomalies
• Monitoring the context information

Security in WSN
Our Proposal
Results
Conclusions
8/19
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Functionalities of the CMA
Introduction

• Broadcast requests
• Analize traffic
• Check the number of messages.
• Below expected ? Find deficient node
• Increase the level of security
• Above expected ? Revoke and change the nodes key
• Increase the level of security

Security in WSN
Our Proposal
Results
Conclusions
9/19
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Functionalities of the CMA
Introduction

• Scan for attacks
• CRC Errors ? Change Channel
• Aggregator DoS ? Revoke and change all the keys
• Increase the level of security
• Compromised node ? Revoke its key
• Send notification to the user and to the
  hospital database
• Power Control Management
• Check the batteries status and send notification
  to the user
• Control the emitting power of nodes and
  aggregator.

Security in WSN
Our Proposal
Results
Conclusions
10/19
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Adaptive Security System Building Blocks
Introduction
Security in WSN
Our Proposal
Results
Conclusions
11/19 (half-time)
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Building Blocks Information procedure diagram
Introduction
Security in WSN
Our Proposal
Results
Conclusions
12/19
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Results

• Aim Find the best compromise between
  performance and security
• Conditions
• Test bed
• - Processor Frequency 540MHz
• - Processing Unit 32 bits
• Real case (Mica2dot)
• - Processor Frequency 4Mhz
• - Processing Unit 8 bits
• Assumptions
• Linear relation between the 2 processing units
• The gain in processing time is equivalent to the
  gain of battery lifetime
• Reference High Level of Security
• Key Exchange frequency 4hours
• Message Sample Rate 10 sec (according to Code
  Blue)

Introduction
Security in WSN
Our Proposal
Results
Conclusions
13/19
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Performances of the System

• Evolution of the processing time and the key
  robustness regarding the level of security

Introduction
Security in WSN
Our Proposal
Results
Conclusions
14/19
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Performances of the System

• Using our simulator and creating a typical day
  scenario, we have obtained the following results

Introduction
Security in WSN
Our Proposal
Results
Conclusions
15/19
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Performances of the System

• Why did we choose 4hours for the key exchange
  frequency?
• Only in the trusted place the time to break the
  key is less than 4 h.
• By increasing the key exchange frequency the
  battery consuming highly increases

Introduction
Security in WSN
Our Proposal
Results
Conclusions
16/19
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Performances of the System

• The influence of the message sample rate on the
  energy consumption

Introduction
Security in WSN
Our Proposal
Results
Conclusions
17/19 (almost done)
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Conclusions
Introduction

• New solution based on the ECC and the
  Diffie-Hellman protocol
• Caution when labeling a place as trusted
• The adaptability of the system increases sensor
  nodes batterys lifetime
• The users behavior is intimately connected to
  the security parameters, i.e. to the battery
  lifetime saved.
• Ability to track the network status and ensure a
  quick response

Security in WSN
Our Proposal
Results
Conclusions
18/19
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• Thank you for your attention
• and Happy New Year ?